The present invention relates to instruments such as transmitters used to measure fluid characteristics in industrial fluid processing plants. In particular, the present invention relates to electrically connecting process transmitters to transmit over an instrument loop in an industrial environment where contaminants may be present.
Process transmitters are used to monitor the operation of industrial processes such as those in oil refineries, chemical processing plants and the like. Process transmitters such as pressure transmitters are typically situated in a fluid processing plant in locations where liquids, dust and humidity and various industrial contaminants may be present. In some environments, process liquids such as an acid or base solution can be present. Liquids can also include spray from hoses used to clean plant equipment. The liquids can drip, splash or spray onto the process transmitter and its electrical connections. Dust, humidity, and liquids in the environment can contaminate and degrade the electrical connections to the process transmitter.
Process transmitters are often fitted with sealed wiring compartments that can be connected with sealed electric conduits to protect the loop wiring and electrical connections from deterioration by contaminants. In the case of a miniaturized process transmitter that uses a header-type connector, however, there is no sealed wiring compartment to protect exposed electrical contact pins in the header from contaminants.
Protective adapters are needed that can connect to contact pins in a header on a process transmitter and that can protect the contact pins and the wiring from contaminants without the addition of a costly and bulky wiring compartment.
With the present invention, An environmentally sealed electrical adapter protects contact pins, contact sockets and wiring from liquids, humidity and other contaminants.
The adapter includes wires that have one end connected to sockets that can be mated with contact pins inside a header on a process transmitter. The adapter can include a sleeve that screws onto the header. The sleeve has a lip that faces toward the cylindrical header.
An environmentally sealing elastomeric part and a washer are compressed between the lip and the cylindrical header. The washer has a washer surface that slides relative to the lip as the threads are tightened. The elastomeric part is compressed and a liquid-proof seal is formed between the elastomeric part and the sealing surface.
The contact pins, contact sockets and wire ends are effectively environmentally sealed by the elastomeric part and protected from damage from environmental contaminants.